Pediatric Medication Dosing Guidelines
Pediatric medication dosages should be calculated based on weight, age, and specific disease considerations, not simply as reduced adult doses. 1 Weight-based dosing is the primary approach for most medications in children, with adjustments needed for age-related physiological differences in drug absorption, distribution, metabolism, and excretion.
General Principles of Pediatric Dosing
Weight-Based Dosing
- For most medications, weight-based dosing is the standard approach
- Children weighing more than 40 kg should generally be dosed as adults 2
- For children under 40 kg, specific mg/kg dosing is required for most medications
Age-Related Considerations
- Neonates and infants <3 months: Require reduced dosages due to immature renal function
- Children 3 months to 2 years: Require careful dose adjustments based on weight
- Children >2 years: Can typically receive standard weight-based dosing
- Adolescents >12 years: May transition to adult dosing depending on weight
Specific Medication Dosing Examples
Antibiotics
Amoxicillin
- Children <3 months: 30 mg/kg/day divided every 12 hours 3
- Children ≥3 months, <40 kg:
- Mild/moderate infections: 25 mg/kg/day divided every 12 hours or 20 mg/kg/day divided every 8 hours
- Severe infections: 45 mg/kg/day divided every 12 hours or 40 mg/kg/day divided every 8 hours 3
- For pneumonia: 90 mg/kg/day divided into 2 doses (or 45 mg/kg/day in 3 doses) 1
Antituberculosis Medications
- Isoniazid: 10-15 mg/kg daily (max 300 mg) 2
- Rifampin: 10-20 mg/kg daily (max 600 mg) 2
- Pyrazinamide: 15-30 mg/kg daily 2
- Ethambutol: 15-20 mg/kg daily 2
Antiviral Medications
Oseltamivir (Influenza)
- Children <1 year: 3 mg/kg per dose twice daily 2
- Children ≥1 year:
- ≤15 kg: 30 mg twice daily
15-23 kg: 45 mg twice daily
23-40 kg: 60 mg twice daily
40 kg: 75 mg twice daily 2
Zanamivir (Influenza)
- Children ≥7 years: 10 mg (two 5-mg inhalations) twice daily for 5 days 2
MDR-TB Medications for Children
Bedaquiline
- Adolescents >12 years and ≥33 kg: 400 mg daily for 14 days followed by 200 mg three times weekly for 22 weeks 2
Linezolid
- Children >12 years: 10 mg/kg once daily
- Children <12 years: 10 mg/kg twice daily 2
Clofazimine
- All children: 2-3 mg/kg daily (maximum 100 mg) 2
Special Considerations
Renal Impairment
- Dose reduction is necessary for children with impaired renal function
- For severe renal impairment (GFR <30 mL/min), specific dosing adjustments are required 3
- Medications primarily eliminated by the kidneys require careful monitoring and dose adjustment
Age-Specific Physiological Factors
- Neonates (<1 month): Have immature hepatic and renal function requiring significant dose reductions
- Infants (1-12 months): Still developing metabolic pathways
- Young children (1-6 years): Higher metabolic rates may require more frequent dosing
- School-age children (6-12 years): Approaching adult metabolic capacity but still require weight-based dosing
Treatment Duration
- For most bacterial infections, treatment should continue for 48-72 hours beyond symptom resolution 3
- For Streptococcus pyogenes infections, a minimum of 10 days of treatment is recommended 3
- For tuberculosis, treatment duration varies by regimen but typically ranges from 6-12 months 2
- For influenza, standard treatment course is 5 days 2
Common Dosing Errors to Avoid
- Using "small adult" doses instead of weight-based calculations
- Failing to adjust doses for renal or hepatic impairment
- Not accounting for age-specific differences in drug metabolism
- Using adult formulations inappropriately for children
- Miscalculating doses when converting between different units or formulations
Practical Approach to Pediatric Dosing
- Calculate dose based on accurate weight measurement
- Consider age-related physiological factors
- Adjust for specific disease state and severity
- Monitor for efficacy and adverse effects
- Reassess dosing as the child grows or clinical status changes
By following these guidelines, clinicians can provide appropriate medication dosing for pediatric patients while minimizing risks of under-dosing or toxicity.